Comparative analysis of ABC, LTP, and WAK families in non-specific immunity of wheat and sunflower.

Plants activate complex defense mechanisms against biotic and abiotic stressors, where non-specific resistance provides broad-spectrum protection. This study presents a comparative bioinformatics analysis of three membrane protein families-ABC transporters, lipid transfer proteins (LTPs), and wall-associated kinase receptors (WAKs)-in winter wheat (Triticum aestivum L.) and sunflower (Helianthus annuus L.). Using public databases, we identified 150 ABC transporters, 80 LTPs, and 55 WAKs in wheat, and 120 ABC, 65 LTPs, and 40 WAKs in sunflower. Structural analysis confirmed conserved domains, including ABC_NBD, TMD, PR-14, and WAK kinase. Transcriptomic data revealed distinct immune strategies: winter wheat effectively implements systemic acquired resistance (SAR), particularly through ABCG transporters (Lr34/Sr57 type) that modulate hormone balance and defense metabolites. In contrast, sunflower predominantly activates a rapid localized immune response (LAR), characterized by ROS signaling triggered by WAK receptors functioning as damage sensors. Functional divergence was observed: wheat WAKs and LTPs are primarily involved in cell wall remodeling and physical barrier induction, while in sunflower, they focus on signaling and membrane stabilization under oxidative stress. Our findings suggest that the evolutionary adaptation of monocots and dicots led to the functional specialization of conserved immune components according to their distinct pathogen spectra and physiological features. These results provide a molecular basis for understanding the diversity of non-specific immunity mechanisms in strategically important crops.